According to the report on world health 2002 of the World Health Organization (WHO), world-wide infectious diseases still are the main cause of death. In particular in the developing countries each year millions of people die from the implications of malaria, sleeping sickness, Chagas-disease, leishmaniosis, candida-infections and other infectious diseases. Whereas in the industrialized countries the classical infectious diseases initially appeared to be defeated (2002: 7% of the fatal cases in Germany), these are progressing world-wide again: Many of the common drugs loose their effect because of the increasing resistance of the pathogens. These also include Gram-positive bacteria, such as staphylococci and enterococci that can cause septicemia and other infections, mainly in immune-suppressed patients. The methicillin and oxacillin-resistant staphylococci (MRSA, ORSA), the vancomycin-resistant enterococci, and the multi-resistant pseudomonades are to be mentioned as particularly problematic germs.
In addition to the increasing generation of resistance of microbial pathogens, their formation of biofilms is a large problem. Biofilms are understood as a community of microorganisms that is coated with an extracellular polysaccharide or protein-matrix, whereby the individual cells are able to stick to another and/or to surfaces (J. W. Costerton, Z. Lewandowski, D. E. Caldwell, D. R. Korber, H. M. Lappin-Scott, Annu. Rev. Microbiol. 1995, 49, 711-745; P. Stoodley, K. Sauer, D. G. Davies, J. W. Costerton, Annu. Rev. Microbiol. 2002, 56, 187-209).
Thereby, the microbial community can be composed of one or even several species. The organization of cells in a biofilm leads to a markedly increased resistance of the overall population against a large variety of influences. Thus, biofilms are not to be understood as a group of individual cells. Rather, they are similar in their physiology to a multicellular organism, in which a different gene expression and metabolic activity, dynamics, and division of labor is found.
Biofilms are widely found in nature. They can be preferably found at the interfaces between the solid and liquid phase, and possibly are the primary life-form of microorganisms in the aquatic milieu (rivers, lakes, oceans, etc.). They also cause an essential economic damage in shipping through the formation of biofilms on those parts of ships that are located under water. Then, these are the organic matrix for the further growth of mussels or bryozoans. This secondary growth on of the hull of ships can reach a thickness of several decimeters, and leads to a drastic increase of the drag of water and thus to a reduction of the maneuverability and the speed of the ships, and to an increased consumption of fuel. Nevertheless, biofilms can also become a threat for humans. Indeed, biofilm-forming human pathogenic bacteria represent an important cause for chronic and recurring infections in human medicine. Prominent examples for this are the formation of plaque on teeth by streptococci, the formation of alginate of Pseudomonas aeruginosa in lung infections in the context of a cystic fibrosis, and, last but not least, the colonization of plastic and metal implants by biofilm-forming staphylococci in modern intensive care medicine.
In view of the increasing importance of nosocomial infections, we have concentrated our attempts on the identification of biofilm-inhibiting drugs against multi-resistant Staphylococcus-aureus and S.-epidermidis-pathogens. These bacteria mainly occur in connection with the use of plastic and metal implants. In particular in immune-suppressed patients they can cause severe general infections that are mainly caused by Staphylococcus epidermidis and Staphylococcus aureus. Both species form biofilms on artificial surfaces (e.g. on venous catheters, pacemakers or on joint replacements) that consist of the bacteria themselves and a polysaccharide matrix. This matrix, which is also designated as Polysaccharide-Intercellular-Adhesin (PIA), consists of β-1,6-bonded glucosaminoglycane-subunits that are substituted with different side groups (D. Mack, W. Fischer, A. Krokotsch, K. Leopold, R. Hartmann, H. Egge, R. Lauts, J. Bacteriol. 1996, 178, 175-183). The substance mediates the adherence of the cells with another, and thus is responsible for the three-dimensional, multi-layered growth of a staphylococcal biofilm. Until today, four proteins, IcaA, IcaD, IcaB, and IcaC, could be identified that are involved in PIA-synthesis (C. Hellmann, O. Schweitzer, C. Gerke, N. Vanittanakom, D. Mack, F. Götz, Mol. Microbial. 1996, 20, 1083-1091; C. Gerke, A. Kraft, R. Süssmuth, O. Schweitzer, F. Götz, J. Biol. Chem. 1998, 29, 18586-18593). The genes that encodes for these enzymes are organized in the so-called icaADBC-operon, which so far was identified in all S.-aureus-isolates as tested, and in 70 to 80 percent of all S.-epidermidis-strains from foreign matter-associated infections (W. Ziebuhr, C. Heilmann, F. Götz, P. Meyer, K. Wilms, E. Straube, J. Hacker, Infect. Immun. 1997, 65, 890-896; S. E. Cramton, C. Gerke, N. F. Schnell, W. W. Nichols, F. Götz, Infect. Immun. 1999, 67, 5427-5433).
Although the PIA, according to all findings so far, is the most important factor for the generation of a biofilm in staphylococci, nevertheless, also additional components are involved in this. It was shown that the establishment of a biofilm takes place in two phases. The first phase first requires the adherence of the staphylococci on the surface, in the second phase followed by the PIA-mediated accumulation of the biofilm. The first phase of the formation of the biofilm, which is also designated as initial adherence, is mediated in S. epidermidis by a surface protein, which is known as AtlE (C. Heilmann, M. Hussain, G. Peters, F. Götz, Mol. Microbial. 1997, 24, 1013-1024). In addition to the initial adherence, AtlE also has another function in the cell of the staphylococcus. It is involved as autolysin-protein in the separation of the cell wall during cellular division. Mutations in the atlE-gene thus lead to an inhibition of the formation of biofilms on surfaces and to a generation of cellular aggregates in the supernatant of the culture (C. Heilmann, M. Hussain, G. Peters, F. Götz, Mol. Microbial. 1997, 24, 1013-1024). Most recently, additional factors were detected that are involved in the formation of biofilms of staphylococci. Members of these are teichoic acids that make up for an essential part of the biofilm-matrix (I. Sadovskaya, E. Vinogradov, S. Flahaut, G. Kogan, S. Jabbouri, Infect Immun 2005, 73, 3007-3017.) Similarly, two surface-associated proteins, Aap and Bap, were identified that can mediate the accumulative phase of the formation of biofilms independently of ica and PIA (H. Rohde, C. Burdelski, K. Bartscht et al., Mol. Microbial. 2005, 55, 1883-1895; C. Cucarella, C. Solano, J. Valle, B. Amorena, I. Lasa, J. R. Penades, J. Bacterial. 2001, 183, 2888-2896.)
Furthermore, for some of the compounds an outstanding activity against trypanosomes could be found. These single-cell parasites are important pathogens in the veterinary, but especially in human, medicine. According to information provided by the World Health Organization, every year 300.000 to 500.000 humans suffer from sleeping sickness that is caused by trypanosoma brucei (A. Stich, P. M. Abel, S. Krishna, BMJ. 2002, 325, 203-206). Without therapy, the disease ends fatally. The medicaments as currently available have a lot of side effects, can not be obtained everywhere, and often are not effective enough. Therefore, new medical options are urgently needed (A. Stich, M. P. Barrett, S. Krishna Trends Parasit. 2003, 19, 195-197).
It is therefore an object of the present invention to provide novel, highly effective and non-toxic substances, which, in particular, can be used for an improved inhibition of the formation of biofilms, as well as for a treatment of diseases, such as, for example, infectious diseases.
This object is solved by the N,C-bonded aryl isoquinolines of the general formulae 1 to 3,
wherein R1 to R6 and R8 to R12 independently are either H, a non-substituted, monosubstituted or polysubstituted C1-C18-alkyl, wherein the alkyl can be straight, branched or cyclic, alkenyl, a non-substituted, monosubstituted or polysubstituted aryl or heteroaryl residue, a non-substituted, monosubstituted or polysubstituted benzyl group, an acyl group, such as, for example, formyl, acetyl, trichloroacetyl, fumaryl, maleyl, succinyl, benzoyl, or a branched or heteroatom- or aryl-substituted acyl group, an alkoxy substituent, such as, for example, —OMe, —OEt, —OnPr, -iPr, —OnBu, —OiBu, —OsecBu, —OtBu, the alkyl group thereof is branched, non-branched or cyclic, an alkyl group bound through a sulfur atom, such as, for example, —SMe, —SEt, or a sulfonyl group, such as, for example, —SO3H, —SO2Me, —SO2CF3, —SO2C6H4CH3 or SO2C6H4CH2Br, or a nitrogen substituent, such as, for example, —NH2, —NHR, —NRR′ (with R, R′=alkyl, aryl etc.), —NC or —NO2, or fluoro, chloro, bromo, iodo, —CN or a hetero substituent,R7 independently can be either H, a non-substituted, monosubstituted or polysubstituted C1-C18-Alkyl, wherein the alkyl can be straight, branched or cyclic, a monosubstituted or polysubstituted, straight, branched or cyclic C1-C18-alkenyl or can be an acyl group, such as, for example, formyl, acetyl, trichloroacetyl, fumaryl, maleyl, succinyl, benzoyl, branched or heteroatom- or aryl-substituted acyl groups,and R8 to R12 can also be bonded in a manner that thereby a non-substituted, monosubstituted or polysubstituted ring and dimers of 1 is generated, as well as pharmaceutically acceptable salts or solvates, with the provisio that the following substances are excluded from the above-mentioned compounds according to the invention:

In view of the increasing importance of hospital-derived infections, the inventors have concentrated their efforts on the identification of novel drugs against multi-resistant Staphylococcus-aureus and S.-epidermidis pathogens, since these are responsible for the largest number of hospital-derived infections. Thereby, not only the approach of searching for those that are effective in the bacteriostatic or bactericidal killing of the pathogens, but particularly those compounds are sought for that interfere with the gene regulation and gene expression of virulence factors. This concept appears to be reasonable in particular with foreign matter-associated staphylococcal infections. Staphylococci form biofilms on plastic and metal surfaces of medical implants, thus representing a major source for persisting and recurring infections. A prevention of the formation of biofilms or their dissolution and removal would markedly contribute to a therapy of nosocomial infections.
A further aspect of the present invention relates to the use of a series of the above-mentioned compounds for a treatment of infectious diseases, such as leishmaniosis and trypanosomal diseases (such as the African sleeping sickness or Chagas-disease). Indeed, it could be found that, upon a modification of the different structural parameters, conveniently the selectivity of the activity can be improved, particularly against a specific pathogen.
A medical applicability of the compounds of the general formulae 1 to 3 as identified according to the present invention was yet unknown. A further aspect of the present invention thus relates to their use for a prevention or treatment of diseases, such as, for example, tumorous diseases or infectious diseases.
A further aspect of the present invention then relates to the use of a compound of the general formulae 1 to 3:
wherein the residues R1 to R12 are as defined above, for an inhibition of the formation of biofilms on surfaces. Preferably, the use relates to an inhibition of the formation of biofilms through staphylococci, such as, for example, S. epidermidis, on plastic and metal surfaces of medical implants, stents, catheters, cannulae, and other medical invasive devices.
A further aspect of the invention relates to the use of the compounds according to the present invention as tools for studying and research of the formation of biofilms, and as “Lead Structures” for the development of additional compounds that inhibit the formation of biofilms and are anti-infective.
In the context of the present invention, a “derivative” shall be a compound derived from the general formulae 1 to 3, which, for example, is substituted in several of the residues as given above for R1 to R12, as well as mixtures of several of these compounds, which, for example, can be converted into a medicament that can be “personalized” for the disease to be treated and/or the patient, respectively, on the basis of diagnostic data or data with respect to the success of the therapy or progress thereof.
A “precursor” of a substance in the context of the present invention shall mean, on the one hand, a substance which during the course of its administration for a treatment is modified by the conditions in the body (e.g. pH in the stomach, or the like) in such a way, or after uptake is metabolized by the body in such a way, that the compounds of the invention or their derivatives are formed as effective substances.
The invention shall now be further described in the following with reference to the attached FIGURE, nevertheless, without being limited thereto.